Quote Originally Posted by dencio1976 View Post
...adjusted to advanced timing for ignition, (since i think lpg has higher octane.. anyone for this correction...),
well, to maximize engine performance, an adjustment to the ignition timing to take advantage of the higher octane value. But this would result in the engine running very rough if you switch back to gasoline.

How many degrees did you advance the ignition from stock?


your post prior to this one is an interesting one. gave me a lot of thinking about upgrading to a better oil. may just be the answer i need. thanks!
Even the current corolla engines have sludge problems and those were running on gasoline.

i thought i mention that lpg has better fuel cost than on gasoline... i alone do the adjustments for the lpg on all our 44 taxis(n still aquiring more). sparkplug color is orange with most. some with red(some drivers prefer their rides faster). white colored sparkplug meant lean n higher temps. black.. rich af mix. im aware of these conditions atleast.
Your sparkplugs are telling you that those engines are running lean. That also might be the cause of your increase valve seal wear. In the very least, it would result in slightly higher engine coolant temperatures.

BTW, the locally available LPG kits used on most cars are very sensitive to air filter condition/quality. A slightly clogged filter will result in a richer air/fuel ratio and also less power from the engine. I tend to clean/replace my filter a bit more often than before. Maybe this could be the root of your problem?